Thank you Peshito for your answer.
All the demos are having the same issue, PdfViewer and also RichTextBox.
Tests done with the default loaded documents in the demos.
Tested on 5 different windows 10s and 3 different Windows Servers 2016 all having French Windows version installed. Printing results on blank pages.
Tried to print to Microsoft PDF printer and have this results : First print, I was asked for the file name, it generates the pdf files, but all pages are blank. Second print : nothing happens, not asked for the file name, no error message.
Tested on a Windows Server with an English version of windows installed : All the scenarios prints the documents correctly.